Application of acetoin as a characteristic identifier in identification of Hainan camellia oil

Abstract

The invention belongs to the technical field of camellia oil type identification, and discloses the application of acetoin as a characteristic identification substance in identifying Hainan camellia oil; also discloses a method for identifying Hainan camellia oil and Guangdong-Guangxi camellia oil based on a characteristic identification substance, and uses gas chromatography-mass spectrometry to detect the relative content of acetoin, a specific volatile substance, in a sample to be tested, and when the relative content value of acetoin in the sample to be tested is greater than 20000000 mAUmin, the sample to be tested is judged to be Hainan camellia oil; when the relative content value of acetoin in the sample to be tested is less than or equal to 20000000 mAUmin, the sample to be tested is judged to be Guangdong-Guangxi camellia oil. The present invention uses acetoin as a characteristic indicator substance, and by detecting the relative content of acetoin in the sample to be tested, Hainan camellia oil and Guangdong-Guangxi camellia oil can be quickly identified.

Description

Technical Field

[0001] The invention belongs to the technical field of camellia oil type identification, and specifically relates to the application of acetoin as a characteristic identification object in identifying Hainan camellia oil. Background Art

[0002] Camellia oleifera Camellia oleifera Camellia oleifera belongs to the genus Camellia of the family Theaceae. It is a natural woody high-end edible oil variety unique to China. It is one of the four major woody oil tree species in the world, along with oil palm, olive and coconut. As an important oil crop in the hilly areas of southern China, the oil-tea tree has rich ecological benefits and economic value. It is widely planted in Jiangxi, Fujian, Hainan, Guangxi and Guangdong. The oil-tea tree grows in warm and humid climate conditions. Its seeds (tea seeds) are rich in oil and have outstanding oil extraction performance. They are widely used in the production and processing of camellia oil to produce high-quality vegetable oil. Compared with olive oil, the oil components of camellia oil are mainly composed of monounsaturated fatty acids and oleic acid, and the similarity is extremely high. It is also known as "Oriental Olive Oil" internationally. Camellia oil is a unique edible oil rich in functional active ingredients such as polyphenols, squalene and phytosterols. It not only has a mellow smell, but also has a pleasant taste.

[0003] Hainan tea oil is called "mountain pomelo oil" by locals. It is rich in unsaturated fatty acids and has always been considered to be of excellent quality. It is golden in color and has a unique aroma. Further research has found that Hainan mountain pomelo oil contains higher concentrations of tea saponins, tea polyphenols and α-tocopherol, giving it higher medical and health value. This quality advantage is not only due to Hainan's unique ecological environment and soil conditions (such as selenium-rich soil), but also because in the long-term natural adaptation process, Hainan oil tea is believed to have evolved into a new species different from inland oil tea.

[0004] In recent years, with the increasing attention of consumers to healthy food, camellia oil, as a vegetable oil with multiple health benefits, has been increasingly in demand in the market. However, due to the high market price and widespread popularity of Hainan camellia oil, a large number of counterfeit products have emerged, which has brought difficulties to consumer rights protection and market order. Therefore, a reliable and accurate characteristic indicator substance and identification method are needed to effectively identify the real Hainan camellia oil. Summary of the invention

[0005] In view of one or more of the above defects or improvement needs in the prior art, a first aspect of the present invention provides the use of acetoin as a characteristic identifier in identifying Hainan camellia oil.

[0006] In the application technology scheme, acetoin is used as a characteristic identification substance in distinguishing Hainan camellia oil and its adulterants, and the adulterants are Guangdong and Guangxi camellia oil.

[0007] In the application technology scheme, gas chromatography-mass spectrometry is used for identification, and the relative content value of acetoin in the sample to be tested is greater than 20,000,000 mAU min, then the sample to be tested is judged to be Hainan camellia oil.

[0008] The second aspect of the present invention provides a method for identifying Hainan camellia oil and Guangdong and Guangxi camellia oil based on a characteristic identifier, comprising the following steps: the characteristic identifier is acetoin, and the relative content of the specific volatile acetoin in the sample to be tested is detected by gas chromatography-mass spectrometry. When the relative content value of acetoin in the sample to be tested is greater than 20000000 mAU, min, the sample to be tested is judged to be Hainan camellia oil; when the relative content of acetoin in the sample to be tested is less than or equal to 20000000 mAU min, the sample to be tested is judged to be Guangdong and Guangxi camellia oil.

[0009] The above-mentioned method for identifying Hainan camellia oil and Guangdong and Guangxi camellia oil based on characteristic identifiers specifically comprises the following steps:

[0010] (1) extracting volatile substances from the oil to be tested as the sample to be tested;

[0011] (2) GC-MS analysis: Take the sample to be tested and perform GC-MS analysis. The location of the acetoin peak is determined based on the retention time and ion fragment information of acetoin. The peak area of ​​acetoin in the sample to be tested is obtained by instrument data processing. The peak area method is used to quantify acetoin and obtain the relative content of acetoin.

[0012] The retention time of acetoin is 3.23±5%min; the ion fragment information of acetoin includes: the quantitative ion is 45, and the qualitative ions are 43, 88 and 27.

[0013] Preferably, in the above identification method, the gas chromatography parameters are as follows:

[0014] Gas chromatography column: HP-5 MS column; helium is used as carrier gas with a flow rate of 1.0-1.2 mL / min, and nitrogen is used as collision gas with a flow rate of 1.3-1.7 mL / min; the injection port temperature is 270-300 °C, and the injection mode is splitless mode; the heating program is as follows: 40 °C for 3 minutes, and then heated to 160 °C at a rate of 2 °C / min. After reaching 160 °C, it is heated to 300 °C at a rate of 50 °C / min and maintained for 3 minutes; the injection mode is splitless mode, and the sample volume is 1.5-2.5 mL; full scan mode is used to detect volatiles, and then these signals are converted to multiple reaction monitoring mode. Preferably, in the above identification method, the mass spectrometry parameters are as follows:

[0015] Inlet temperature: 270-300 °C, injection volume: 0.8-1.2 μL, split ratio: 10:1; MS 4-stage rod temperature: 150-170 °C, ion source temperature: 230-250 °C;

[0016] The ion source is EI;

[0017] The collision energy is 70 eV;

[0018] Helium was used as carrier gas with a flow rate of 1.0-1.2 mL / min, and nitrogen was used as collision gas with a flow rate of 1.3-1.7 mL / min;

[0019] Scan mode: full scan (SCAN), scanning range m / z 50-650.

[0020] Preferably, in the above identification method, in step (1), HS-SPME solid phase microextraction is used to extract volatile substances, and the solid phase extraction head sample enriched with volatile substances is inserted into the gas chromatography injection port for data acquisition and analysis.

[0021] Preferably, the above identification method uses Agilent MassHunter MS quantitative software to perform quantitative analysis on acetoin.

[0022] The present invention has the following beneficial effects:

[0023] The present invention proposes for the first time that acetoin can be used as a characteristic indicator substance to distinguish Hainan camellia oil from Guangdong and Guangxi camellia oil. By detecting the content of acetoin in the tea oil sample to be tested, Hainan camellia oil and Guangdong and Guangxi camellia oil can be quickly and accurately distinguished, and has the advantages of simple operation, low cost, high detection efficiency, etc. And the content of acetoin can be quantitatively detected by gas chromatography and mass spectrometry in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is the secondary characteristic fragment pattern of acetoin. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Unless otherwise specified, the methods involved in the following embodiments are all conventional methods.

[0027] Example 1: Acquisition and Detection Analysis of Camellia Oil Samples

[0028] (1) Selection of experimental materials

[0029] Camellia species of the Camellia genus in tropical and subtropical regions of China were selected, including 11 populations from Hainan Province, 4 populations from Guangdong Province and Guangxi Zhuang Autonomous Region. A total of 15 populations were collected, and three biological replicates were performed for each population (i.e., 3 samples were taken from each population), totaling 45 samples (i.e., the Camellia species used in this example were all tropical / subtropical Camellia species, the difference being the different growing locations).

[0030] (2) Obtaining oil products

[0031] Select full and healthy camellia seeds grown in Hainan and Guangdong and Guangxi in the current year, crack the shells, peel and crush, put into an oven (75℃) and dry with hot air until constant weight. After the camellia seeds are cooled to room temperature, they are pressed with an oil press (LYF-898 screw oil press), and the crude oil obtained by pressing is precipitated and the supernatant oil is taken.

[0032] Take 2 mL of each sample to be tested and mix them, and use them as quality control samples (QC samples) to test together with the samples to be tested.

[0033] (3) GC-MS analysis of oil products

[0034] The volatile substances were extracted by HS-SPME solid phase microextraction, and the samples were preheated at 50 °C for 10 min and adsorbed at 50 °C for 20 min. The solid phase extraction head was inserted into the injection port, and the compound components were analyzed by gas chromatography (Agilent 7890A gas chromatograph, Agilent Technologies, USA) and Agilent 7000D gas chromatography-mass spectrometer.

[0035] The gas chromatography conditions were as follows: HP-5 MS capillary column (30 m×0.25 mm×0.25 μm; Agilent) was used as the gas chromatography column to separate the compounds. The temperature program was as follows: 40 °C for 3 minutes, then heated to 160 °C at a rate of 2 °C / min, and then heated to 300 °C at a rate of 50 °C / min after reaching 160 °C, and then held for 3 minutes. The injection mode was splitless mode, the sample volume was 2 mL, the injection port temperature was 270 °C, and a 0.75 mm inlet liner (Agilent Technologies) was built in. High-purity helium (He, 99.999%) was used as the carrier gas and high-purity nitrogen (N 2 , 99.999%) as collision gas, with flow rates of 1.0 mL / min and 1.5 mL / min, respectively; full scan was used to detect volatiles, and then these signals were converted to multiple reaction monitoring mode. At the same time, after the sample test was completed, the QC samples were tested under the above conditions to ensure the quality of the test.

[0036] The mass spectrometry conditions were as follows: the ion source was EI; the MS 4-pole temperature was set to 150 °C, the ion source temperature was 230 °C; the collision energy was 70 eV; the injection port temperature was set to 270 °C, the injection volume was 1 μL, and the split ratio was set to 10:1; the carrier gas was high-purity He (99.999%) at a flow rate of 1.0 mL / min; the collision gas was 99.999% high-purity N 2 , flow rate: 1.5 mL / min; mode: full scan (m / z 50-650).

[0037] (4) Qualitative and quantitative analysis of acetoin

[0038] The volatile metabolite data of the test sample and QC sample were imported into Qualitative Navigator B.08.00 software. When the similar retention time (Rt) signal was 3.23, the test sample had a peak (the peak offset was no more than 0.2 min). According to the NIST database, this signal was qualitatively identified as acetoin (C 4 H 8 O 2 ). Secondary characteristic fragments of acetoin ( Figure 1 ) ions are: Qualifier ion 1 (m / z 45); Qualifier ion 2 (m / z 43); Qualifier ion 3 (m / z 88); Qualifier ion 4 (m / z 27).

[0039] Based on the qualitative results, the Agilent MassHunter quantitative analysis (MS) software was used to quantitatively analyze the acetoin metabolites and QC samples. The ion with high peaks and specificity was selected as the quantitative ion (i.e., m / z 45), and a 1-min range window was set before and after the given RT to prevent peak drift, and the data was manually integrated and corrected.

[0040] The experimental results are shown in Table 1 below.

[0041] Table 1 Acetoin content in camellia oil at different sampling points

[0042]

[0043] The experimental results show that acetoin is an effective characteristic indicator substance for distinguishing Hainan camellia oil from Guangdong and Guangxi camellia oil. According to the quantitative results, it can be judged whether the sample is Hainan camellia oil. When the acetoin content in the sample is greater than 20000000 mAU min (peak area is used to represent relative content), it is judged to be Hainan camellia oil. On the contrary, if the value of acetoin in the sample to be tested does not reach this value (less than or equal to 20000000 mAU min), it is judged to be camellia oil from Guangdong and Guangxi regions (Guangdong Province and Guangxi Zhuang Autonomous Region).

[0044] The invention can identify Hainan camellia oil and Guangdong and Guangxi camellia oil by detecting the acetoin content in the sample to be tested, and has the advantages of simple operation, low cost, high detection efficiency, etc. The application of the characteristic indicator substance of Hainan camellia oil provided by the invention will not only improve consumers' cognition and selection ability of camellia oil quality, but also provide important technical support for establishing a sound camellia oil standardization management system.

[0045] Example 2: Identification method of Hainan camellia oil and Guangdong and Guangxi camellia oil based on characteristic identifiers of the present invention

[0046] The method for identifying Hainan camellia oil and Guangdong and Guangxi camellia oil based on characteristic identifiers of the present invention is operated according to the following steps:

[0047] (1) Extracting volatile substances from the oil to be tested as the sample to be tested: using HS-SPME solid phase microextraction method to extract volatile substances, inserting the solid phase extraction head sample to be tested enriched with volatile substances into the gas chromatography injection port for data acquisition and analysis.

[0048] (2) GC-MS analysis: Take the sample to be tested and perform GC-MS analysis. The location of the acetoin peak is determined based on the retention time and ion fragment information of acetoin. The peak area of ​​acetoin in the sample to be tested is obtained through instrument data processing. The peak area method is used to quantify acetoin and obtain the relative content of acetoin.

[0049] The gas chromatography parameters are as follows:

[0050] Gas chromatography column: HP-5 MS column; helium was used as carrier gas with a flow rate of 1.0 mL / min, and nitrogen was used as collision gas with a flow rate of 1.5 mL / min; the injection port temperature was 270 °C, and the injection mode was splitless mode; the heating program was as follows: 40 °C for 3 minutes, then heated to 160 °C at a rate of 2 °C / min, and after reaching 160 °C, heated to 300 °C at a rate of 50 °C / min and maintained for 3 minutes; the injection mode was splitless mode, and the sample volume was 2 mL; full scan was used to detect volatiles, and then these signals were converted to multiple reaction monitoring mode. The mass spectrometry parameters are as follows:

[0051] Inlet temperature: 270 °C, injection volume: 1.0 μL, split ratio: 10:1; MS 4th pole temperature: 150 °C, ion source temperature: 230 °C;

[0052] The ion source is EI;

[0053] The collision energy is 70 eV;

[0054] Helium was used as carrier gas with a flow rate of 1.0 mL / min, and nitrogen was used as collision gas with a flow rate of 1.5 mL / min;

[0055] Scan mode: full scan (SCAN), scanning range m / z 50-650.

[0056] The retention time of acetoin is 3.23±5%min (preferably 3.23±0.2 min); the ion fragment information of acetoin includes: the quantitative ion is 45, and the qualitative ions are 43, 88 and 27.

[0057] Agilent MassHunter MS quantitative software was used for quantitative analysis of acetoin.

[0058] When the relative content of acetoin in the sample is greater than 20,000,000 mAU min, the sample to be tested is judged to be Hainan camellia oil; when the relative content of acetoin in the sample to be tested is less than or equal to 20000000 mAU min, the sample to be tested is judged to be Guangdong and Guangxi camellia oil.

[0059] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. The application of acetoin as a characteristic identification substance in distinguishing Hainan camellia oil and its mixed products is characterized by: The mixed product is camellia oil from Guangdong and Guangxi.

2. A method for identifying Hainan camellia oil and Guangdong and Guangxi camellia oil based on characteristic identifiers, characterized in that: The method comprises the following steps: the characteristic identification substance is acetoin, and the relative content of the specific volatile substance acetoin in the sample to be tested is detected by gas chromatography-mass spectrometry, so as to identify Hainan camellia oil and Guangdong and Guangxi camellia oil.

3. The identification method according to claim 2, characterized in that: The steps include: (1) extracting volatile substances from the oil to be tested as the sample to be tested; (2) GC-MS analysis: Take the sample to be tested and perform GC-MS analysis. The location of the acetoin peak is determined based on the retention time and ion fragment information of acetoin. The peak area of ​​acetoin in the sample to be tested is obtained by instrument data processing. The peak area method is used to quantify acetoin and obtain the relative content of acetoin. The retention time of acetoin is 3.23±5%min; the ion fragment information of acetoin includes: the quantitative ion is 45, and the qualitative ions are 43, 88 and 27.

4. The identification method according to claim 3, characterized in that: The gas chromatography parameters are as follows: Gas chromatography column: HP-5 MS column; helium was used as carrier gas with a flow rate of 1.0-1.2 mL / min, and nitrogen was used as collision gas with a flow rate of 1.3-1.7 mL / min; the injection port temperature was 270-300 °C, and the injection mode was splitless mode; the heating program was as follows: 40 °C for 3 minutes, then heated to 160 °C at a rate of 2 °C / min, and after reaching 160 °C, heated to 300 °C at a rate of 50 °C / min and held for 3 minutes; full scan was used to detect volatiles, and then these signals were converted to multiple reaction monitoring mode.

5. The identification method according to claim 3, characterized in that: The mass spectrometry parameters are as follows: The MS 4th pole temperature was set to 150-170 °C, and the ion source temperature was set to 230-250 °C; The ion source is EI; The collision energy is 70 eV; Helium was used as carrier gas with a flow rate of 1.0-1.2 mL / min, and nitrogen was used as collision gas with a flow rate of 1.3-1.7 mL / min; Scan mode: full scan, scanning range m / z 50-650.

6. The identification method according to claim 3, characterized in that: In step (1), HS-SPME solid phase microextraction is used to extract volatile substances, and the solid phase extraction head sample enriched with volatile substances is inserted into the gas chromatography injection port for data acquisition and analysis.

7. The identification method according to claim 3, characterized in that: Agilent MassHunter MS quantitative software was used for quantitative analysis of acetoin.

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